Autonomous flights may be encountered in various circumstances such as for example, when an aircraft suffering from a failure of its aircrew is placed under the command of an automaton or of a remote authority situated on the ground or in another aircraft, with a view to bringing it back to the ground under the best safety conditions both as regards the occupants of the aircraft and the residents of the zones overflown or else when a drone returns prematurely to its base after a break in its command link with the ground.
Since it became apparent that a civilian aircraft could be hijacked to serve as a weapon of destruction, emphasis has been placed on systems and methods making it possible to bring an aircraft back to the ground without the assistance of its crew while as far as possible minimizing the risks incurred by the residents of the regions overflown and by the occupants of the aircraft. All the known systems and methods propose that control of the aircraft be taken over, after detecting a crew failure situation, by an automatic onboard facility which takes charge of the flight controls while dispossessing the crew thereof, either to follow in an emergency a predefined flight plan, selected, from among a set of flight plans stored in a database, as being that whose route is the closest to the current position of the aircraft, or to give command of the aircraft to a ground station or to another aircraft ensuring direct piloting or providing a flight plan to be followed in an emergency. A few known systems and methods make provision to warn aircraft deploying in the vicinity and the air traffic control centers, of the emergency situation facing the aircraft onboard which they are carried, but none of them concern themselves with the proper insertion into the air traffic of the new flight plan adopted as an emergency so that the air traffic control authorities are compelled to organize an evacuation of the airspace in a wide vicinity around an aircraft in an emergency situation so as to avoid any risk of collision.
The same necessity to evacuate the airspace and to stop all air traffic in the vicinity of an aircraft arises when the aircraft is a drone which, for one reason or another, is no longer commanded from the ground and follows, in an autonomous manner, a return flight plan to its base.